The house at Mound B was 17 feet in diameter. It had an extended entranceway on the southeast side, a centrally located hearth prepared of clay, and several interior roof supports. This house had been built directly on the surface of the floodplain.
There were two houses at Mound C, the smaller one (14 feet in diameter) superimposed over the larger one (18 feet in diameter). Each apparently had a centrally located hearth and one, or possibly both, had an extended entranceway on the west side. Two interior roof support molds were related to the earlier house, but none were found for the later one.
Beneath Mound D was a single house with traces of an interior hearth situated near the center and an extended entranceway on the west side. Instead of being built directly on the surface of the floodplain as were the houses at Mounds B and C, the house at Mound D had been built in a shallow excavated pit.
Underneath each of the interior hearths associated with the houses at Mounds B and C was a relatively large post mold. It is uncertain whether there was a similar post mold at Mound D because the large pothole there had removed the central portion of the house floor, including the hearth. These molds at Mounds B and C apparently mark the locations of center posts which were used as work platforms during construction of the houses and then removed after the houses were completed. Ridges of sand around the perimeters of all the houses seem to have been banked against the exterior walls while the houses were standing. The floodplain between and around the mounds was tested by pitting and trenching, but no occupational features or concentrations of cultural material were found away from the mounds.
Circular houses of the same general architecture as those at the Harroun Site are typical of the Caddoan Area, especially during the Fulton Aspect period (Webb, 1940; Harrington, 1920; Newell and Krieger, 1949; Goldschmidt, 1935; Davis, 1958). Harrington (1920) reported several circular houses with extended entranceways found beneath sand mounds one to three feet high in southwestern Arkansas. Some of these houses had been built on the surface of the ground, some had been built in shallow pits, and others had been placed on low mounds. Most of them had been burned, and all were associated with typically Caddoan artifacts and with burned clay daub. Harrington thought the houses were earth lodges which had burned and collapsed, the earth from the walls and roofs falling over the house floors so as to form mounds. Webb (1940) reported architecturally similar houses at the Belcher Site in northwestern Louisiana, but presented a strong argument that they were wattle-and-daub houses and not earth lodges.
It appears certain that the Harroun houses were also wattle-and-daub structures without any covering of earth. This conclusion is based on the following points:
1. The bodies of the mounds were composed of soft sand entirely unsuited for covering the sides and roofs of houses. It is doubtful if sand of this consistency would stick to a vertical or steeply sloping wall at all; but even if it did, it would surely be washed away with the first heavy rain.
2. The central portions of the Harroun mounds stood from two to three feet above the floors of the houses. If all this sand had fallen in from the tops of earth lodges, then the lodges must originally have had sand piled at least two or three feet thick on the middle of their roofs. This does not seem probable.
3. Fragments of burned, wattle-impressed, clay daub at all the Harroun houses indicate that the houses were plastered with clay, presumably on the outside. Burned clay daub apparently does not occur archeologically in association with true earth lodges in the plains.
4. Remains of true earth lodges in the Plains area show superficially as depressions, often with a low ring-shaped mound around the perimeter (Wedel, 1936: 24; Lehmer, 1954). Sometimes the depressions result in part from the shallow pits in which the lodges were built. But even when an earth lodge was built directly on a flat surface rather than in a pit, the mound left behind when the lodge collapsed has a concavity in the center instead of being convex as were the mounds at the Harroun Site. It is significant that Mound D was prominent and convex in shape even though the house it covered had been built in a pit. Certainly it is difficult to visualize an earth lodge—whether built in a pit or not—collapsing in such a manner as to produce a smoothly convex mound like those at the Harroun Site.